Autism May Increase Risk of Early Parkinson's, Finds New Research

Autism and Parkinson’s may be more connected than previously thought. A study has shown that people with autism are more likely to develop Parkinson’s, raising a new alarm about long-term brain health care.

Autism spectrum disorder (ASD) is a neurodevelopmental condition that affects how a person communicates, interacts socially and perceives the world. Parkinson’s disease is a progressive neurological disorder that usually appears later in life, mainly affecting movement but also impacting mood and cognition.

Although the conditions differ in age of onset and symptoms, they both involve brain function and, in recent years, scientists have begun to investigate whether there are biological links between them.

The idea is that certain brain processes altered in autism may, over time, also be linked to diseases such as Parkinson’s.

Researchers have been investigating whether people with ASD are at higher risk of developing other neurological conditions later in life. A large new study from Sweden has shed some important light on the possible link between ASD and Parkinson’s disease (PD), a neurological condition that affects movement control and usually appears in adulthood.

In the study, scientists followed more than 2.2 million people born between 1974 and 1999 to see if they would develop Parkinson’s by 2022. The participants were aged 29–42 years, being 1,106,772 women (48.6%). Just over 51,000 of the participants had been diagnosed with ASD.

What they found was that while Parkinson’s remains rare in young people, those with ASD had more than double the rate of Parkinson’s diagnosis compared to people without ASD (0.05% versus 0.02%).

Even after accounting for other factors that could influence this risk, such as depression, use of antidepressants and antipsychotics, family history of mental illness, and socioeconomic status, the association between ASD and Parkinson's remained significant.

This suggests that autism may be linked to a higher risk of developing Parkinson's later in life. In addition, the researchers found that people with ASD also had a higher frequency of depression and use of antidepressant or antipsychotic medications.

These factors were also linked to an increased risk of Parkinson’s, but did not fully explain the link with autism. This suggests that there may be a shared biological basis between ASD and Parkinson’s, something that is still being investigated.

In summary, this study reinforces the need to pay attention to the long-term neurological health of people with ASD. Although the risk of Parkinson’s is still low in young people, understanding these connections may help to prevent or better treat these conditions in the future.

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Risk of Parkinson Disease in Individuals With Autism Spectrum Disorder

Weiyao Yin, Abraham Reichenberg, Michal Schnaider Beeri, Stephen Z. Levine, Jonas F. Ludvigsson, Martijn Figee, and Sven Sandin

JAMA Neurol. Published online May 27, 2025. 

doi:10.1001/jamaneurol.2025.1284

Abstract:

Recent research suggests a plausible biological link between autism spectrum disorder (ASD) and Parkinson disease (PD). Nonetheless, large longitudinal studies examining the risk of PD following ASD are lacking. To examine the association between ASD and future PD risk. A nationwide population-based prospective cohort study was performed using data from Swedish national registers. All individuals born in Sweden from 1974 to 1999 with follow-up from age 20 years until December 31, 2022, and with complete covariate data were included. The analysis was completed in August 2024. Diagnoses of ASD as a time-varying exposure obtained from the National Patient Register. Diagnoses of PD were obtained from the National Patient Register through 2022. The relative risk (RR) of PD was quantified using incidence rate ratios with 95% CIs from Poisson regression. Preterm birth, depression, antidepressant use, and antipsychotic exposure over time were potentially modifying life events. The study included 2 278 565 individuals (median [IQR] age at exit, 34 [29-42] years; 1 106 772 female [48.6%]), contributing 33 858 476 person-years. PD occurred in 438 of 2 226 611 individuals without ASD (0.02%; 1.3 cases/100 000 person-years) and 24 of 51 954 individuals with ASD (0.05%; 3.9 cases/100 000 person-years) (RR, 4.43 [95% CI, 2.92-6.72]). The risk estimates were similar after adjusting for sex, socioeconomic status, family history of mental illness, family history of PD, and age at ASD diagnosis. Preterm or early-term birth was not associated with and did not modify the PD risk. Depression and antidepressant use (present in 24 257 individuals with ASD [46.7%]) were associated with increased risk of PD (RR, 2.01 [95% CI, 1.40-2.88]), independent of ASD. Antipsychotic exposure (present in 16 387 individuals with ASD [31.5%]) reduced but did not fully attenuate the association (RR, 2.00 [95% CI, 1.27-3.14]) and showed no interaction with ASD on PD risk. ASD was associated with increased risk of PD, even after adjusting for depression or antidepressant use and antipsychotic exposure. These findings suggest a potential shared etiology between neurodevelopmental disorders and PD, and a heightened awareness of long-term neurological conditions in individuals with ASD may be warranted.